Gallium implanted at a 45 degree angle
on a 50 um diameter silicon pillar
etched 60 um tall
The Al2O3 mask was deposited by reactive magnetron
sputtering, the pattern is defined by lift off technology.
The Ga has been implanted by FIB:
Dose ~ 2*1016 cm-2
Ga doping of ~ 6*1021 cm-3
Implant depth ~ 35 nm +/- 12.5 nm ->
total mask thickness is 25 nm
Sputtered Alumina Etch Masks give a high selectivity
and are easy to remove with BHF or NH4OH (RCA -1 clean).
Gallium FIB Implanted Etch Mask show good selectivity,
are easy to patter, 3-D patterning is still under investigation.
This results have been obtained at
the Hertz Foundation
M. David Henry, Axel Scherer, Michael Shearn